Refrigeration system

ABSTRACT

A refrigeration system, in which a venturi tube consisting of two closely opposite nozzles, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port, is arranged in the refrigerant cycle, and the exit of the venturi tube is connected with a gas-liquid separator, the upper end of which is connected to a refrigerant tank by way of a condensor, and further said refrigerant tank is connected to an evaporator by way of an expansion valve, the exit of the evaporator being connected with said suction port of the venturi tube, while, the bottom end of the gas-liquid separator is directly connected with the refrigerant tank or a refrigerator oil tank and said refrigerant tank or refrigerator oil tank is further connected to the entrance of the venturi tube through a driving pump. In the present system, it results in an advantage that the power required for driving the system is markedly reduced.

United States Patent [191 Hosokawa June 18, 1974 REFRIGERATION SYSTEM [76] Inventor: Toshio Hosokawa, Midorigaoka 2-6-5-503, Meguro-ku, Tokyo, Japan [22] Filed: June 14, 1973 [21] Appl. No.: 369,963

Primary ExamiherWilliam J. Wye Attorney, Agent, or FirmMcGlew and Tuttle [5 7] ABSTRACT A refrigeration system, in which a venturi tube consisting of two closely opposite nozzles, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port, is arranged in the refrigerant cycle, and the exit of the venturi tube is connected with a gas-liquid separator, the upper end of which is connected to a refrigerant tank by way of a condensor, and further said refrigerant tank is connected to an evaporator by way of an expansion valve, the exit of the evaporator being connected with said suction port of the venturi tube, while, the bottom end of the gas-liquid separator is directly connected with the refrigerant tank or a refrigerator oil tank and said refrigerant tank or refrigerator oil tank is further connected to the entrance of the venturi tube through a driving pump. In the present system, it results in an advantage that the power re quired for driving the system is markedly reduced.

2 Claims, 6 Drawing Figures PA'TENTEnJuu 18 mm 3.8 171155 SHEET 1 BF 3 FIG.1

ix! '4 5 QT mimmmw m4 3.8171155 sum 2 or 3 FIG. 4

REFRIGERATION SYSTEM The present invention relates to a new refrigeration system. More particularly the invention relates to a refrigeration system substituting a venturi tube for the compressor of piston type or centrifugal fan type which has been employed in the conventional refrigeration system.

The refrigeration system according to the present invention comprises: a venturi tube arranged in the refrigerant cycle, the exit of said venturi tube being connected to a separator for separating liquid refrigerant from gas refrigerant; a refrigerant tank to which, gas refrigerant separated in said separator is conducted through a condensor, and liquid refrigerant separated in said separator is directly conducted; and, an evaporator connected with said tank through an expansion valve, the exit of said evaporator being connected with the suction port of the venturi tube.

An object of the invention is to provide a refrigeration system reducing the power required for driving the system in comparison with the conventional refrigeration systems.

Another object of the invention is to provide a refrigeration system having simple construction in comparison with the conventional systems.

Still another object of the invention is to provide a refrigeration system facilitating the custody thereof in comparison with the conventional systems.

Further objects of the invention will become apparent from the following explanation of the invention referring to the accompanying drawings, in which:

FIG. 1 is a diagrammatic flowsheet showing an embodiment of the refrigeration system according to the invention.

FIG. 2 is a similar flowsheet to that of FIG. 1 but showing another embodiment.

FIG. 3 is a graph showing the heat cycle of refrigerant drawn on the Mollier diagram in a conventional refrig' eration system, in which the numerals in parentheses indicate concrete values in case of adopting ammonia as refrigerant.

FIG. 4 is a graph showing the pressure change of refrigerant in the venturi tube of the system of the invention.

FIG. 5 is a graph showing the relation between the constriction ratio of the venturi tube and the pressure depression caused during the circulation of refrigerant in the present system.

FIG. 6 is a graph showing the relation between the compression ratio of the refrigerant in the venturi tube and the flow ratio of the same (supply rate/suction rate).

Referring to FIG. 1, the refrigerant tank I is connected with the venturi tube 3 through a driving pump 2, and said venturi tube 3 consists of two closely opposite nozzles 3a and 3a, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port 3b thereby. The exit of the venturi tube 3 is connected with a gas-liquid separator 4, the upper end of which is connected to a condensor 5, the exit of said condensor 5 being connected with the refrigerant tank I, while, the bottom end of the gasliquid separator 4 is directly connected with the refrigerant tank 1. The tank 1 is further connected to an evaporator 7 by way of an expansion valve 6, the exit of the evaporator 7 being connected to the suction port 3b of said venturi tube 3.

Thus, in accordance with the system of the invention, the liquid refrigerant circulates in such a way as, tank I pump 2 venturi tube 3 gasJiquid separator 4 tank 1, whereby the pressure of refrigerant in the suction port 3b decreases. Accordingly, the gas refrigerant having generated in the evaporator 7 is sucked into the suction port 3b of the venturi tube 3 and is further sent to the exit of the venturi tube 3. That is, the gas refrigerant circulates in such a way as, evaporator 7 suction port 3b of venturi tube 3 gas-liquid separator4 condenser 5(liquefies hereafter) tank 1 expansion valve 6 evaporator 7 (vaporizes again), whereby the refrigerant takes heat from a fluid to be cooled in the evaporator 7 and gives heat to a fluid to absorb heat in the condensor 5.

The conventional refrigeration system has, so to speak, a mechanism reversing the heat engine cycle. FIG. 3 is a graph showing the heat cycle drawn on the Mollier diagram, that is, on the diagram of entropy i pressure p of refrigerant in the conventional system, in which the clockwise ABCD shows the heat engine cycle and the counterclockwise DCBA shows the refrigeration cycle. In the refrigeration cycle, the evaporation of refrigerant, i.e., heat absorption takes place between CB, theadiabatic compression thereof takes place between 13A, the condensation thereof, i.e., heat generation takes places between AD and thgadiabatic expansion thereof takes place between DC, respectively.

Accordingly, the required power in the conventional refrigeration system corresponds to the work to compress the refrigerant bet w een BA, and the ratio of the refrigerating capacity (CB) to the required power, i.e., performance coefficient amounts to 5-6 at most, though such performance coefficient varies with the kinds of refrigerant and the conditions of the compression. On the contrary, in the system of the present invention the performance coefficient thereof amounts to 30 and upward by means of adopting the venturi tube.

FIG. 4 is a graph showing the pressure change of refrigerant in the venturi tube of the present system, in

which: P shows the pressure at the entrance of the venturi tube, P shows that at the suction port and P shows that at the exit of the venturi tube, respectively. That is, the refrigerant, the pressure of which is increased to P, by the pump 2, enters the venturi tube 3, and the velocity head thereof increases at the entrance-side nozzle of the venturi tube 3 to decrease the pressure thereof in the suction port 3b. At this time a portion of the refrigerant evaporates to increase the volume thereof, thereby the velocity head of the refrigerant increases more and more to decrease the pressure thereof to P in the suction port 3b. Thus, the gas refrigerant coming out of the evaporator 7 is sucked into the suction port 3b, and the velocity head thereof decreases at the exit-side nozzle of venturi tube 3, thereby the pressure of refrigerant returns; to static pressure of P followed by entrance of the refrigerant into the condensor 5 so as to be condensed therein.

As described above, the power required for driving the pump in the system of the invention does not be in proportion to P but is in proportion to (P -P i.e., to the pressure depression of the refrigerant.

The required power in the refrigeration system of the invention is evaluated in such a way as shown below: Adopting R-l2 (dichlorodifluoromethane) as refrigerant under the conditions that refrigerating capacity 86,400 kcal/hr, the condensing pressure 9.42 kg/cm and the evaporating pressure 1.94 kg/cm the required power is 62 HP and the performance coefficient is 2.1 in the conventional system, while, in the present system, the required power decreases to 2.3 HP and the performance coefficient increases to 60.3. Further, in case of adopting ammonia as refrigerant under the conditions that the refrigerating capacity 864,000 kcal/hr, the condensing pressure 18.8 kg/cm and the evaporating pressure 2.41 kg/cm the required power is 547 HP and the performance coefficient is 2.46 in the conventional system, while, in the present system the required power decreases to 9.8 HP and the performance coefficient increases to 137.7.

On the other hand, the power required theoretically in the conventional refrigeration system is calculated from FIG. 3 in such a way as follows, for example, in case of circulating ammonia at a rate of 1 kg/sec (470-397) kcal/kg X 3,600 kg/hr 262,800 kcal/hr 410 HP However, in the refrigeration system according to the invention, the external work by the adiabatic expansion of the liquid refrigerant at the outlet of the entranceside nozzle of venturi tube 3, is as follows (397-157) kcal/kg X 3,600 kg/hr X 0.20 167,300 kcal/hr 262 HP Accordingly, when both the evaporating rate of refrigerant in the evaporator 7 and the supplying rate of that to the venturi tube 3 amount to l kg/sec respectively, the said work corresponds to 0.639 time of the above theoretically required power. Such work is furnished by the evaporation heat generated through the evaporation ofa portion (20 percent) of liquid refrigerant at the outlet of the entrance-side nozzle of venturi tube 3.

1n the embodiment of the present system, in which the rate of gas refrigerant coming out of the evaporator 7 is 1 kg/sec, the rate of the gas refrigerant which is generated, at the venturi tube as described above, from the liquid refrigerant sent from the pump 2 is required to be 3.2 times of l kg/sec, so that the flow rate of refrigerant required to supply to the venturi tube amounts to 16 kg/sec( 3.2+0.20= l6 Therefore, the work accomplishing by the present system amounts to 0.639 X 16 10.2 times of the required power. The ratio of driving steam energy to evaporated steam energy in the conventional water cooling mechanism of steam-jet type is approximately 9). As described above, the sucked gas refrigerant decreases the velocity head thereof at the outlet of the exit-side nozzle of the venturi tube so as to increase the pressure therein, so that the work by the adiabatic compression has eventually no relation to the power for driving the pump 2.

FIG. shows a graph in case of graduating the ratio of said pressure depression to the suction pressure in the venturi tube on the Y-axis, and graduating the constriction rate ofthe venturi tube (B on the X-axis, the

constriction ratio signifying the ratio of areas of both outlet and inlet of the entrance-side nozzle of the venturi tube 3. Taking conditions that the specific gravity of refrigerant is 1,000 kg/M, the delivery velocity of the pump is 4 M/sec and the constriction rate is 0.1, the reduction of pressure owing to the increase in velocity head of the refrigerant will be as follows P -P y/2g (V VE) 1,000/2g (1,600-16) 80,816 kg/M 8.0816 kg/cm In case of the above conditions, the measured pressure depression was as follows:

P -P 1.212 kg/cm C X (P -P FIG. 6 shows a graph, graduating the ratio, of the amount of gas refrigerant generated, as abovedescribed, from the liquid refrigerant which is sent through the pump 2, to the amount of gas refrigerant sucked from the evepoartor 7, on the Y-axis, and graduating the compression ratio on the X-axis, said compression ratio signifying the ratio of refrigerant pressure (P at the exit of the venturi tube to that (P at the suction port 3b of the same. From the above FIG. 6, the ratio of the amount of gas refrigerant may be readily known from the compression ratio.

As described above, in the refrigeration system of the invention, a marked advantage that the required power is markedly small in comparison with that in the conventional systems, results in.

In the refrigeration system of the present invention, refrigerator oil can further be used together with the refrigerant which is sparingly miscible with such refrigerator oil. Fig. 2 shows a flowsheet of such an embodiment, in which the refrigerator oil is compressed by the pump 2 and sent to the venturi tube 3 so as to generate negative pressure in suction port 3b thereof, whereby gas refrigerant coming out of the evaporator 7 is sucked. The cycle of refrigerator oil is constructed in such a way as, oil tank 11 pump 2 venturi tube 3 gas-liquid separator 4 oil tank 11, while the'cycle of gas refrigerant is constructed in such a way as, evaporator 7 venturi tube 3 gas-liquid separator 4 condenser 5 (1iquefies hereafter) refrigerant tank 1 expansion valve 6 evaporator 7. In the above case, it results in an advantage that the required amount of refrigerant (e.g., ammonia may be reduced.

What I claim is:

l. A refrigeration system comprising: a venturi tube connected to a refrigerant tank through a driving pump, said venturi tube consisting of two closely opposite nozzles, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port; a gas-liquid separator connected with the exit of the venturi tube, the upper end of the gas-liquid separator being connected to said refrigerant tank through a condensor, while the bottom end of the gasliquid separator being directly connected with said refrigerant tank; and, an evaporator connected to said refrigerant tank through an expansion valve, the exit of said evaporator being connected with said suction port of the venturi tube.

2. A refrigeration system comprising: a venturi tube connected to a refrigerator oil tank through a driving pump, said venturi tube consisting of two closely opposite nozzles, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port; a gas-liquid separator connected with the exit of the venturi tube, the upper end of the gas-liquid separator being connected to a refrigerant tank through a condensor, while the bottom end of said gasliquid separator being directly connected with said refrigerator oil tank; and, an evaporator connected to said refrigerant tank through an expansion valve, the exit of said evaporator being connected with said suction port of the venturi tube.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,817 ,055 Dated June 18 1974 lnventofls) QShio I-Iosokawa It is certified that error appears in the aboveidentifiec1 patent and that said Letters Patent are hereby corrected as shown below: 4

On the cover sheet insert:

[30] Foreign Application Priorit Data Japan 64106 June 28 1972 Signed and sealed this 1st day of October 1974.

(SEA Attest:

MCCOY M. GIBSON JR. c. MARSHALL Dt-xNN Commissioner of Patent:

Attesting Officer USCOMM-DC 60376-P69 u.s GOVERNMENT PRINTING OFFICE: 8 930 F ORM r c-1050 (10-69) 

1. A refrigeration system comprising: a venturi tube connected to a refrigerant tank through a driving pump, said venturi tube consisting of two closely opposite nozzles, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port; a gas-liquid separator connected with the exit of the venturi tube, the upper end of the gas-liquid separator being connected to said refrigerant tank through a condensor, while the bottom end of the gas-liquid separator being directly connected with said refrigerant tank; and, an evaporator connected to said refrigerant tank through an expansion valve, the exit of said evaporator being connected with said suction port of the venturi tube.
 2. A refrigeration system comprising: a venturi tube connected to a refrigerator oil tank through a driving pump, said venturi tube consisting of two closely opposite nozzles, the neighbouring part of such opposing ends of the nozzles being tightly closed so as to form a suction port; a gas-liquid separator connected with the exit of the venturi tube, the upper end of the gas-liquid separator being connected to a refrigerant tank through a condensor, while the bottom end of said gas-liquid separator being directly connected with said refrigerator oil tank; and, an evaporator connected to said refrigerant tank through an expansion valve, the exit of said evaporator being connected with said suction port of the venturi tube. 